This is an incredibly tough issue for parents and their teenage or young adult children. No matter how open or welcoming you have been to conversation on this topic with your daughter, it is likely that she truly fears that you will be negative and disapproving of her desire to begin sexual relations with her boyfriend. In truth, most parents understandably have large concerns about their child becoming sexually active. It is a huge turning point in both of your lives.
It sounds like there is some degree of health and maturity in her decision to have sex with her partner. It appears that she is in what is probably a stable relationship (I would consider it “long-term” for someone in her age-group) and she is doing the right thing by trying to learn about contraception and sex. I would certainly support you in trying to talk about this with her but give yourself some time to move beyond your immediate emotional reactions before initiating the conversation. Don’t be surprised if she really doesn’t want to talk to you about it and simply isn’t willing to do so. On the other hand, you may be pleasantly surprised.
It is appropriate for you to share your thoughts, feelings and concerns with her about her choices, but please don’t leap to the conclusion that she has already decided in favor of having sex. She may still be in a process of making a decision. While you may be able to influence her decision-making, there is actually little you can do at this stage to deter her if she has already decided to go forward.
Your best bet is to support her but with an emphasis on safety and what you see as healthy and unhealthy reasons for becoming sexually active. The potential for unwanted pregnancy or STDs should be your main concern. You other main concern would be not creating a serious rupture in your mother-daughter relationship.
If your religious values are extremely strong about teen sex and premarital sex, this will be a monumental challenge for you. You might seek someone who is knowledgeable and trustworthy with whom you can discuss your feelings and concerns. Perhaps your family physician or a counselor who is experienced in working with teens can help you cope with this new development in your daughter’s life.
Your daughter’s decision is not a reflection on you being a good or bad parent. There are many other influences in an older teen’s life and the values and norms of society continue to change. Life is complicated and our children’s lives seldom unfold as we would wish them to. In my opinion, the love and connection between you and your daughter is ultimately the greatest value to consider here. Take the long-term view and know that you have given her a good foundation for living a healthy and rewarding adult life.